Electrochemical Behavior and Surface Chemistry of Nonequilibrium Aluminum Alloys: Passivity Mechanism and Fabrication Methods

Abstract : The electrochemical behavior of sputter-deposited nonequilibrium stainless aluminum alloys and different methods to produce bulk or thick-film material have been investigated. Nonequilibrium Al-Ta and Al-W alloys exhibit enhanced passivity over a wide pH range even though the passive film chemistry varies considerably. This enhanced passivity can be explained by the Solute-Rich Interphase Mechanism (SRIM) which states that formation and passivation of occluded cells stabilize the passive film from continued Cl attack and dissolution. The best material is produced by sputter deposition, however, physical vapor deposited and plasma sprayed material also exhibit some enhanced passivity. Approved for public release, Distribution unlimited, Reproduction in in whole or in part is permitted for any purpose of the United States Government.